Intumescent Coating

Definition - What does Intumescent Coating mean?

Intumescent coating is a layer of protective substance which works by chemical reaction generated by heat, resulting in swelling and formation of an insulating layer on the surface, with or without release of water.

This type of coating provides a cost-effective as well as practical solution for fire protection and corrosion protection of structures made of alloys and steel, and can also be used in a decorative capacity.

Corrosionpedia explains Intumescent Coating

An intumescent substance increases in volume and reduces in density when exposed to heat. It is a passive fire retardant and fire protector which is able to insulate steel surfaces from further thermal attack.

It is classified according to the substances used. Those containing hydrates produce a soft, swollen barrier that is a poor heat conductor and releases water vapor to act as a fire retardant.

Coatings containing sodium silicates or graphite produce hard layers which are beneficial for plastic firestops and uncovered steel structures. These coatings are used for firestopping, gasketing, retarding and windows' casings for coastal buildings, marine and offshore structures, aircraft as well as ships.

In the case of fire, some coatings soften, react and decompose to form a carbon barrier. A foaming agent produces foam and a non-flammable gas, thus the layer expands tremendously to create an effective barrier.

Intumescent substances also provide anticorrosion protection to steel surfaces, thus enhancing the useful life of the structures.

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